【简答题】灼烧过的BaSO 4 沉淀质量为0.5013g,其中有少量的BaS,用H 2 SO 4 溶液润湿,使BaS转变成BaSO 4 ,过量的H 2 SO 4 蒸发出去,再灼烧,称得沉淀质量为0.5021g,求BaSO 4 中BaS的质量分数。
【单选题】My little brother bas never been to Beijing, but it's the place ______ .
A.
where he'd like to visit
B.
he most wants to visit
C.
in which he'd like to visit
D.
that he wants to visit it most
【判断题】05-2-19*在tRNA分子中,除四种基本碱基(A、G、C、U)外,还含有稀有碱基。
【简答题】直接写得数: 2818-168= 1÷ 2 j = 2 5 ×2.5= j 7 ÷j= 7j.5-j.z6= 4 z ÷ z 4 = 4 5 + j 4 = j 4 ÷8.75=
【单选题】下列关于肺泡表面活性物质的描述,错误的是
【简答题】include<stdio.h> void main() {int i,j,a[4][4]; for(i=0;i<4;i++) for(j=0;j<4;j++) a[i][j]=1+i;--j; for(i=0;i<4;i++) {for(j=0;j<4;j++) if(a[i][j]>0)printf('%3 d',a[i][j]); printf('/n');} }